Hingeless dental clamp



July 14, 1953 w. E. MATHISON HINGELESS DENTAL CLAMP Aug I f QM feres.

Patented July 14, 1953 OFFICE 2,645,014 HINGELESS DENTAL CLAMP Wegor E. Mathison, Glen Ellyn, Ill. Application August 8, 1952, Serial No. 303,255

This application relates to a new and improved dental clamp, and is a "continuation in part of United States patent application Serial v No. 9.191; filed April 23, 1949. I

j As explained in that application, a plicant seeks to provide a simple means for holding a matrix against the outside surface of a porcelain" filling in a cavity until its surface has set, and thereby permit the'dentist to proceed with other work. The small clamp shown in the copending application accomplishes this end very satisfactorily where the dentists other work is in a laboratory or for another patient, for he may leave the patient for the requisite five or "tenminutes while the porcelain sets,'and this 'settingwill occur under circumstances more fa- I ad personally held vorable than if the dentisth the matrix in position.

However, there are many times when it is very desirable to proceed immediately to work on other teeth in the same patients mouth and applicant has found that the clamp shown in the' copending application, small though it is-only one and three-quarters of an'inch long'inter- The-principal object of thisinvention is to eliminate the use of a hinged clamp while obtainingthe same action as such a clamp. A feature of this invention is the mounting of the moldable material on the ends of facing sides of-a V-shaped metal 'member whichfis bendable and strong, but completely inelastic. By simply squeezingthis member betweentwo teeth so that the moldable material, i. e., guttapercha, engages the matrix, the metal holds its position, because it is dead-completely inelastic. A spray of air cools the gutta-percha and the hingeless clamp holds itself and the guttapercha in the extreme, constricted position' attained by the fingers. 1 I f The second object of this invention is to providea clamp which is so small that when it is inffposition, it will not interfere with working upon'other teeth of the same patient.

These clamps employ the gutta-percha molding material described in the copending application. The' dental supply houses and dentists term the material used' for temporarily filling cavities temporary stopping. Its principalingradient is gutta-perch'a which has properties almost unique. In a wide range of temperatures, gutta-percha becomes moldable but does not flow. In using, a dentist need not fear the gutta-perchas dripping. Secondly, guttapercha has high surface adhesive qualities through-a wide range of temperatures. J It can be'adheredto metal, and asthetemperature:1n-

condition 1 7 Claims. (Cl; 32-63) creases, it will hold onbetter than'when the temperature is lower. Finally, and most importantly for applicants purpose, gutta-percha is completely inelastic at almost all temperatures. At roomtemperature, it is comparatively hard but can be cut with a knife. The edges of thecut are not smooth but frayed, indicating that the gutta-percha is somewhat frangible. When heated, the frangibility is almostcompletely lostbut still there is no elasticity. The

substance continues dead. Also, deformation does not require much pressure.

These and such other objects as may here- "inafter appear are attained by the embodiment of the invention shown in the accompanying drawings, wherein:

Fig. '1 is a perspective view of applicants clamp, "much enlarged;

Fig; 2 is a side elevation of theclamp in flat Fig.' 3 is a back view'of applicants clamp in flat condition;

Fig. 4 is a side elevation illustrating how the clamp is held between the thumb and index finger immediately before applying to teeth;

Fig. 5 is a reproduction of Fig.- 8 of the copending application and illustrates in cross section the position'of the gutta-percha and arms "of applicants hingeless dental clamp when holding a matrix in'place;

Fig. '6 is a perspective viewof a modified form of clamp wherein the tangs have been struck out of the body of'the clamp; and

Fig.7 is an enlarged perspective view of half of applicants clamp illustrating a removable g'utta-percha pad.

Continuing to refer to the drawings, applicant's clampfconsists of a strip of flat metal l0 bent to an included angle of somewhat less than A major part of this invention derives from the characteristics of the material of which -this strip I0 is made. The

material must have no elasticity. Applicant has experimented with many copper, steel, zinc and lead alloys.- One good composition is composed principally of lead. The essential element is lack of elasticity while nevertheless being bendable by finger compression. Applicant currently uses a substantially pure lead sheet having a thickness of .045 inch, and in the exact form shown in Figs. 2 and .3, the bending line with this gauge of metal will have the requisite strength.

. Referring to Fig. 4, the two arms 14 and I6 are pressed against the teeth by the thumb l8 and the index finger 20. The fingers pinch as tightly as they can. The composition and the thickness of the strip I and the amount of metal along the line I2 must be sufficiently strong to hold the two arms I4 and I6 to whatever constriction the fingers can pinch them. Additionally, the arms themselves must have no elasticity. If there is elasticity so that the arms spring back outwardly, the gutta-percha has already adhered to the matrix and will draw it away from the surface of the filling.

Returning to Fig. 1, the two arms I4 and I6 each have holes 22 therethrough and scalloped edges 24 for the purpose of forming irregular gripping surfaces for the gutta-percha pads 26, which are applied at a temperature where they are moldable. Extending rearwardly from each arm are lugs or tangs 28 and 30. These tangs provide a gripping surface for the fingers. Without them, the fingers would slip off the end of the clamp because the over-all length of the clamp in flat condition as shown in Figs. 2 and 3, is only one and one-eighth inches and it is difficult to hold. The tangs 28 and 30 project from the surface of the clamp by only threethirty-seconds of an inch. Their outer ends 32 are blunt so as not to perforate the finger and when pressure is brought down hard, the fingers actually press right down to the flat surfaces of the arms I4 and I6.

In use, the clamp is squeezed between two teeth as illustrated in Fig. 5, and at the point where the fingers can no longer squeeze the clamp, the metal base holds it. In Fig. 5, the arms I4 and I6 are U-shaped in cross-section. The figure comes from the-copending application. In applicants present structure, the arms I4 and I6 are rectangular in cross-section.

In Fig. 6, the tangs 50 and 52 are stamped from the body of the clamp. The strip is a little heavier than the one used in Fig. 1 because the lands 54 are narrow. The thickness of the material must be sufficient to resist deformation by the pressed gutta-percha. In order that the hand may be able to bend the clamp, applicant widens or narrows the connecting land 56, Fig. 3.

The composition of the pads 26 is principally gutta-percha. Gutta-perch in its natural state is. somewhat elastic. In the form delivered to dentists, it has very little elasticity at any useful temperature. It is commonly called temporary'stopping. It is principally gutta-percha, but contains some filler material.

Attention is invited to the fact that the clamp shown in Fig. 1 differs from that in Figs. 2 and 3 at the line of bending. The embodiment in Figs. 2 and 3 has its edge inwardly scalloped at the bending line, whereas that in Fig. 1 does not. This is to emphasize the point that the gross weight of metal at the bend can be varied in two ways-either by changing the gauge of metal or by varying the width of the land.

In Fig. 7, applicant illustrates a removable gutta-percha pad 34 having a flat under surface 36 and a bead or wale 38. clamp 42 has an opening 44 into which the wale 38 may seat. The clearance will be sufilciently close so that a dentist can insert the pads 34 and still have them held in position. The metal composition of the clamp is such that it can The arm 40 of the v be bent only a few times before breaking. The

removable gutta-percha or temporary stopping pad may assume considerable importance commercially, as contrasted with the fixed pad because gutta-percha or temporary stopping even when kept in a closed box dries out or the action of air makes it more brittle. Dentists keep only small supplies on hand. The average dentist would use from three to six of these clamps a day. If sold in boxes of 100, with the guttapercha already on the arms, after several weeks the clamps in the box might have unsatisfactory gutta-percha on the arms. It may work out, therefore, that the clamps will be sold in the form shown in Fig. 7 with the gutta-percha inserts separate. Moreover, as stated'heretofore, it is practical to bend the clamp along the line I2 of Fig. 1, two or three times and have it work satisfactorily. This replaceable gutta-percha pad, therefore, would enable the dentist to get more usage out of his clamp.

Having thus described his invention, applicant claims:

1 A dental clamp comprising an integral elongated member of manually bendable, inelastic material, anda pad of moldable material composed principally of gutta-percha disposed on the same side of each end of said member.

2. A dental clamp comprising an integral elongated fiat member of manually bendable, inelastic material, and a pad of moldable material composed principally of gutta-percha disposed on the same side of each end of said member.

3. A dental clamp comprising an elongated member of manually bendable, inelastic metallic material, a pad of moldable material composed principally of gutta-percha disposed on the same side of each end of said member, and two tangs projecting from that side of the elongated member opposite to the side carrying the guttapercha pads, one on each side of the longitudinal center of the clamp.

4. A dental clamp comprising an integral flat piece of manually bendable, inelastic metallic material having a v-shaped configuration as viewed from one side so as to form two arms, and a pad of moldable material composed principally of gutta-percha disposed on the inside face of eacharm.

5. A dental clamp comprising an elongated, fiat member of manually bendable, inelastic material having a V-shaped configuration as viewed from a long side so as to form two arms, a pad, of moldable material composed principally of guttapercha disposed on the inside end of each arm. and ,a tang struck outwardly from the wall of each arm.

6. A dental clamp comprising an elongated. flat member of manually bendable, inelastic material having a V-shaped configuration as viewed from a long side so as to form two arms, a pad of moldable material composed principally of guttapercha disposed on the inside end of each arm. and a tang struck. outwardly from the wall of each arm, said tang being struck from a central portion of said arm.

7. A dental clamp comprising an integral, elongated member made of acomposition consisting principally of lead having a V-shaped configuration as viewed from along side, the member along the line of the V being bendable under finger pressure, and a pad of moldable material composed principally of gutta-percha disposed on the inner sideof each arm of the clamp.

WEGOR E. MATHISON.

Name Date Hollingsworth Mar. 30, 1915 Siqveland Oct. .8, 1940 Number 

